1. Field of the Invention
The present invention relates to a transporting apparatus, and more particularly, to a transporting apparatus in which two driving units having a plurality of links are interlocked to easily transport articles such as a semiconductor assembly.
2. Description of the Related Art
Generally, a semiconductor manufacturing system includes a transporting apparatus to automatically transmit a semiconductor assembly such as a wafer, a liquid crystal display LCD substrate, etc., in order to enhance work efficiency through an automated manufacturing line. A selective compliance assembly robot arm (SCARA) transporting apparatus has been mainly used. Recently, however a parallel transporting apparatus has been used because it has a simple structure as compared with that of the SCARA transporting apparatus and is useful in a vacuum condition.
The conventional parallel transporting apparatus has two driving units having a plurality of links interlocked in parallel so as to transport a semiconductor assembly. For example, there is disclosed a transporting apparatus in U.S. Pat. No. 6,189,404, titled“ROBOT FOR HANDLING”, in which the driving units are interlocked at a concentric axis by links and rotate about a coaxial driving axle, thereby reciprocating a transporting table. There are various other transporting apparatuses disclosed in U.S. Pat. No. 5,180,276, titled “ARTICULATED ARA TRANSFER DEVICE”, and in U.S. Pat. No. 5,647,724, titled “SUBSTRATE TRANSPORT APPARATUS WITH DUAL SUBSTRATE HOLDERS”.
In the conventional transporting apparatuses, the transporting links are connected to rear opposite sides of an oblong transporting table. Accordingly, even a small load on the transporting table causes a large moment. Stress due to the large moment is concentrated on pivots placed in the rear opposite sides of the transporting table and connecting the transporting table with the transporting links, so that the load of a transportable semiconductor assembly is limited to be relatively light. To overcome the above problems, there is additionally needed an accessory such as a bearing, etc., to support a heavy semiconductor assembly.
Further, in the conventional transporting apparatuses, the driving axles to drive driving links are symmetrically provided from left to right or coaxially. Accordingly, in the case of a dual X-type transporting apparatus including two transporting tables, the structure of the driving axles is complicated or the driving links may have a four-tiered structure to avoid an interference with each other, allowing production cost of the transporting apparatus to increase.